1. Field of the Invention
The present invention relates to a bush bearing of male and female clinch type having at least two joints.
2. The Prior Art
A joint configuration in a conventional wrapped bush bearing been of two types including a butt joint type and a clinch type, which are used properly in compliance with the purposes of use. In general, the butt joint type is widely utilized from the economic point of view, while the clinch type is employed when needed from the functional point of view.
It is usual that the wrapped bush bearing having either one of the above-mentioned two types of joint configuration has a single joint. The wrapped bush bearing having a single joint has the following disadvantages.
(a) If the bush bearing is manufactured only by press forming, accuracy in out of roundness of the bush bearing is low as compared with a split type bearing.
(b) If the bush bearing is of tapered type, the yield of material is low. Specifically, a bearing stock having a width of the finished bearing is first bent into a cylindrical body, and then the opposite axial end faces of the cylindrical body are machined into a requisite tapered bush configuration. Thus, the tapered bush bearing is low in yield of material.
(c) The yield of material is also low when a longitudinal direction of a bearing strip is aligned with the direction in which the bush bearing is wrapped. The reason for this is that, when blanking is performed in the strip, it is necessary to take into account an allowance margin or a cutting margin in the vicinity of each of mating portions of the bush bearing, because the mating portions are different in configuration from each other.